B-tree strategy functions

The btree_ops operator class defines the names of strategy functions for the btree access method.

The strategy functions that the btree_ops operator class defines are:
  • lessthan (<)
  • lessthanorequal (<=)
  • equal (=)
  • greaterthanorequal (>=)
  • greaterthan (>)

These strategy functions are all operator functions. That is, each function is associated with an operator symbol; in this case, with a relational-operator symbol. For more information about relational-operator functions, see the HCL Informix® User-Defined Routines and Data Types Developer's Guide.

When the query optimizer examines a query that contains a column, it checks to see if this column has a B-tree index defined on it. If such an index exists and if the query contains one of the relational operators that the btree_ops operator class supports, the optimizer can choose a B-tree index to execute the query.


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